loop1: detected capacity change from 0 to 1024
=====================================================
BUG: KMSAN: uninit-value in __hfsplus_ext_read_extent fs/hfsplus/extents.c:167 [inline]
BUG: KMSAN: uninit-value in __hfsplus_ext_cache_extent+0x7cb/0x990 fs/hfsplus/extents.c:191
 __hfsplus_ext_read_extent fs/hfsplus/extents.c:167 [inline]
 __hfsplus_ext_cache_extent+0x7cb/0x990 fs/hfsplus/extents.c:191
 hfsplus_ext_read_extent fs/hfsplus/extents.c:218 [inline]
 hfsplus_file_extend+0x7b5/0x1df0 fs/hfsplus/extents.c:459
 hfsplus_get_block+0xfc3/0x1a20 fs/hfsplus/extents.c:245
 __block_write_begin_int+0xa73/0x3030 fs/buffer.c:2145
 block_write_begin fs/buffer.c:2256 [inline]
 cont_write_begin+0x10e1/0x1bc0 fs/buffer.c:2594
 hfsplus_write_begin+0x85/0x130 fs/hfsplus/inode.c:48
 generic_perform_write+0x365/0x1050 mm/filemap.c:4175
 __generic_file_write_iter+0x213/0x460 mm/filemap.c:4292
 generic_file_write_iter+0x131/0x980 mm/filemap.c:4318
 do_iter_readv_writev+0x9cd/0xc00 fs/read_write.c:-1
 vfs_writev+0x52a/0x1500 fs/read_write.c:1057
 do_pwritev fs/read_write.c:1153 [inline]
 __do_sys_pwritev2 fs/read_write.c:1211 [inline]
 __se_sys_pwritev2+0x22f/0x480 fs/read_write.c:1202
 __x64_sys_pwritev2+0xe4/0x150 fs/read_write.c:1202
 x64_sys_call+0x37d0/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:329
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_frozen_pages_noprof+0x689/0xf00 mm/page_alloc.c:5171
 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2416
 alloc_frozen_pages_noprof+0xf7/0x200 mm/mempolicy.c:2487
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab+0x24d/0x1220 mm/slub.c:2660
 new_slab mm/slub.c:2714 [inline]
 ___slab_alloc+0xff3/0x3470 mm/slub.c:3901
 __slab_alloc mm/slub.c:3992 [inline]
 __slab_alloc_node mm/slub.c:4067 [inline]
 slab_alloc_node mm/slub.c:4228 [inline]
 __do_kmalloc_node mm/slub.c:4375 [inline]
 __kmalloc_noprof+0xa96/0x1310 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __bch2_folio_create fs/bcachefs/fs-io-pagecache.c:130 [inline]
 bch2_folio_create fs/bcachefs/fs-io-pagecache.c:143 [inline]
 bch2_folio_set+0x37a/0x1d50 fs/bcachefs/fs-io-pagecache.c:189
 __bch2_buffered_write fs/bcachefs/fs-io-buffered.c:864 [inline]
 bch2_buffered_write fs/bcachefs/fs-io-buffered.c:1026 [inline]
 bch2_write_iter+0x1b05/0x61c0 fs/bcachefs/fs-io-buffered.c:1082
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe2/0x15d0 fs/read_write.c:686
 ksys_write fs/read_write.c:738 [inline]
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746
 x64_sys_call+0x3014/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 7642 Comm: syz.1.456 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
=====================================================